1. Field of the Invention
This disclosure relates to guidance systems for projectiles, missiles, and other ordinance that engages targets by detecting and following laser light scattered from the targets.
2. Description of the Related Art
Laser guided ordinance is commonly used to engage point targets with a high probability of success and minimal collateral damage. Such ordinance includes guided artillery projectiles, guided missiles, and guided bombs, all of which will be referred to herein as “projectiles”.
A laser guided projectile typically includes a semi-active laser (SAL) seeker to detect pulsed laser electro-magnetic radiation (EMR) scattered from the intended target and to provide signals indicative of the target bearing such that the projectile can be guided to the target. The SAL may include a non-imaging optical system to capture and focus the scattered laser EMR onto a detector. The optical system may convert the target bearing to an irradiance distribution or “spot” positioned on the detector. As the target bearing changes the position of the spot on the detector changes. In order to provide high sensitivity, the SAL optical system may have a large aperture and high optical efficiency.